The invention relates to a footwear support system of the type positioned within the inner volume of an article of footwear. Footwear support systems often are configured to include a footbed and an insole insert attached to the footbed. Certain footwear support systems absorb shock during walking, running or other forms of exercise, thereby minimizing the possibility of injury to the wearer""s foot and joint. Such footwear support systems also increase the support for the wearer""s foot and provide greater comfort. Since the footwear support system is in direct contact with the wearer""s foot, it is important that it anatomically conforms to the wearer""s foot.
The invention features a footwear support system of the type positioned within an inner volume of an article of footwear (e.g., shoe or boot) and having an insole insert attached to a footbed.
In a general aspect of the invention, the footbed of the footwear support system includes a body having an upper surface and a cavity formed within the upper surface for receiving an insole insert. The cavity is defined by a peripheral region of the body which extends upwardly from the upper surface of the body. The cavity has a shape corresponding to the shape of the insole insert and a depth corresponding to the thickness of the insole insert.
In another aspect of the invention, a footwear support system includes the footbed described above and a corresponding insole insert.
In still another aspect of the invention, a footwear support system includes the footbed described above and a pair of interchangeable insole inserts, each having a thickness corresponding to the predetermined depth of the cavity. The second interchangeable insole insert has properties different from that of the first interchangeable insole insert.
Because the cavity has a shape and depth corresponding to the shape and thickness of the insole insert, the footwear support system has a uniform surface, which anatomically conforms to the wearer""s foot. Edges or corners formed by differences between the thickness of the insole insert and the depth of the cavity are virtually eliminated. As a result, the footbed provides greater comfort to a wearer""s foot.
Embodiments of these aspects of the invention may include one or more of the following features.
The depth of the cavity may be in a range between 0.06 inches and 0.25 inches. The thickness of the insole insert may be slightly higher than the predetermined depth of the cavity to allow for compression from a wearer""s foot. The body of the footbed may include a polymer selected from a group consisting of polyurethane, EVA, polyethelene and TPU""s. The footbed further may include an outer support region surrounding the peripheral region. The outer support region may has a bottom surface adapted to conform to the inner volume of the article of footwear, and a top surface adapted to support a peripheral portion of a sole of a wearer""s foot.
In one embodiment, the insole insert may include hydrophilic urethane. The insole insert may further include additives such as absorptive fillers, fibrous materials, surfactants, odor absorbents, bactericides, pH buffers, rubber particles and thermal phase change particles. In another embodiment, the footbed may be made from a urethane system and the insole insert may be made from a hydrophilic urethane formulation. The insole insert may be permanently attached to the cavity of the footbed.
In the embodiments of the aspect including a pair of interchangeable insole inserts, the interchangeable insole insert may be attached non-permanently to the cavity of the footbed using a velcro fastening system. For example, in one embodiment of this aspect, the first insole insert includes hydrophilic urethane for insulating a wearer""s foot in cold environments. The second insole insert, on the other hand, has properties for cooling a wearer""s foot in warm environments. For example, the second insole insert can be formed from urethane foam or other lightweight and relatively high clo material such as Thinsulate(copyright) or Lite Loft(copyright), products of Minnesota Mining and Manufacturing Company, St. Paul, Minn. These insulative inserts generally include a fabric laminate cover. Further details relating to other materials for forming insole inserts can be found in U.S. Pat. No. 5,763,335, entitled xe2x80x9cComposite Material for Absorbing and Dissipating Body Fluids and Moisturexe2x80x9d, which is incorporated herein by reference.
Interchangeability of insole inserts is particularly advantageous where the article of footwear is used in different environments or under different wearing conditions.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.